Bits and pieces. Too often we see progress in riding as what we have achieved, how fast we can go, how high we can jump. People are always in a rush to just see how they can get their horse to listen. To create the ideal horse, we have to balance the mind and the body. Any horse is capable of this, once you understand, there is no such thing as a horse that will always be spooky, always bolt, always buck, or even just has a bad attitude. What we see as behavior problems are usually just holes somewhere along in the training. Once we get a grasp on the horses mind, we only make that more solid as we work on the horses body. This is what is lacking in many NH Guru's teachings. Even all of the "disengagement of the hind end" is very dangerous for a horse if the horse doesn't have proper flexion through the stifles (which most do not).
A rider has the ability to make a horse feel better. We usually get on the horse thinking of what the horse can do for us. People want to ride because it makes them feel good, we focus on the horses behavior because that is what we need to make a successful ride with no "rebellion". However, we will find the most cooperative horse on the ground and under saddle can be difficult to catch because their constant obeying causes them physical pain. Being around a person makes them hurt instead of feel better. Have you ever gotten on a horse and had your first thought be "what can I do for you today?". Once you do, you begin what can be very slow and tedious work (you can't start going to the gym today and have a model body tomorrow, right?). Most horses have postures that would make us cringe if we saw a human carrying their bodies the same way, but many people don't see it, they see a "big butt" or "pretty colors". A lot of horses are also crooked through their bodies, try sticking your butt out, stomach to the left, head to the right, and chin in the air and walk, this is how many horses that I see are traveling. My own horse was stuck here at one point, completely obedient except he dropped his shoulder in his left lead around corners. I did walk work only with him for several months, decided to ask for canter one day and we didn't fall around corners!
As a trained rider, we have the ability to feel small differences, and fix those differences. It is as physically taxing on the rider, and may not be the most relaxing ride, but will be rewarding.
Here is a ride I had on a horse I had leased out, in detail (horse requires a lot of fixer upper work, will never again do that)
Horse was leased for 1 year, no longer backed up, saddle that had fit for years was suddenly sliding back, refused to use hind end when came home.
Back was dropped behind withers, left side half in higher than right, barrel was shifted to left to take weight off of right leg since right hip was out. Tight hamstrings, weak quads and gluteal muscles, tightness in the neck causing mane to flip closer to the poll, horse had been leaning on the bit and using that as balance, heavy movement on front legs.
Ride - started out pressed as far back in the saddle as I could, requiring tightening of my gluteals, back flat, abs in, rib cage pressed out, lifting front of pelvis off saddle, slightly more pressure on left side, closing in left thigh until horse swapped to right, switch seat pattern. Bring lower leg back on side with more weight, encouraging tightening of her abdominals and lifting of the back. Minimal rein use with this particular horse, she tends to over use the riders hands, so I don't give her the option and just work primarily through seat and leg. Takes about 20 minutes before the horse finally releases some of the tension through the topline and lets her head drop, encourage with leg to track up with hind legs and tip pelvis forward. Hold as long as she can until she falls back out to the left, rinse and repeat.
I never came out of the walk for 1 hour, I fixed the right hip manually from the ground, that helped out in the ride. I worked my butt off, but she was much more relaxed and willing when the ride was over than once she started. When she realized the small things I was asking made her body feel better, she showed less resistance. It will probably take several weeks of this 5 times a week before being able to go to trot, but the horse will be more willing for the work, as she will feel better after each session.
I can also tell you that 90% of horse owners wouldn't even see a physical problem with this horse, no lameness, just stubborn - refuses to back up, impatient - rushes forward, lays on riders hands, choppy - hard gaits to ride as she is dropping her back, not flexing through her joints, and holding head in the air, unwilling - moving while cinching, nervous for mounting.
This may be completely confusing, but given the other things I mentioned going on in her body before I got on her, would you want to be ridden if you were her? I can go on and on, but I probably just completely bored you. Plus I gotta run, buh-bye.